Like many others, when I first started out, I was getting killed left and right within seconds and not knowing what is going on or where to go.

Me, in a nutshell.

You know the awareness of your surroundings, to be aggressive yet cautious, and ultimately be tactful and outsmart your enemies.

After you play a while, everything will basically just come to you naturally, trust me.

While being on a team that tend to play together (usually the winning team too) makes it much easier to accomplish, being on a team where you see everyone being scattered just makes it super hard.

You basically already said this yourself. If your team is coordinated, you're going to win, clearly. If your team has no idea what they're doing, it's really no matter of how "hard" it is to win. Plain and simple, you're just going to attempt to carry your whole team knowing you lost. You, as a single person, can't force everyone to stick together. Your team has no idea what they're doing at that point. Just take the defeat and move on.

And I just feel like reading the map is not as simple as if enemies have A and you have B, then they should be coming from A’s direction.

You'd be surprised how accurate this is if all the enemy team cares about is just running straight from objective to objective with zero disregard to any form of conventional tactics, which happens frequently.

There are times where I felt like everything clicked because I was able to really go cover to cover, see enemies before they see me, and sometimes catch them off guard for like a short kill streak, then few hours later when I’m in a game where we are getting blown out, everything would just fly out the window, and I would just suddenly not know what to do anymore.

Might not be you; welcome to this game's wonderful (lack of) team balancing. You can play a game where you're doing great, next game, nothing works right. Seems like you're trying to focus on yourself as the issue, when I doubt that's what it is. Depends basically on everyone else in the game at this point.

And overall it just feels like these tips and guides are effective only when things are simple but as soon as shit hits the fans when your half of your team is dead, and the rest all scattered I just wouldn’t know how to adapt anymore.

This is why you should take all of the guides with a grain of salt; they just don't accurately represent exactly how YOU play. A good baseline, sure. Goes back to the above, though. You can try your absolute best and still get destroyed if your team is awful at this point. If there's zero coordination, you're bound to fail. It's more on the team as a whole, and less to do with you.

So how do the great player survive and maintain a good KDR and high points even when their team is getting dominated?

Probably because they're too busy sitting on the edge of the map going for kills instead of going for the objective, which is also probably the reason why the is getting dominated in the first place. Not entirely sure with the correlation of high points, though. I've typed enough.